Although it has been widely reported that four commercial aircraft were hijacked over the United States on September 11, 2001, what is less well known is that while the terrorist attacks were taking place and for many hours after, numerous additional aircraft gave indications that they had been hijacked or, for other reasons, were singled out as potential emergencies. More than 20 aircraft were identified as possible hijackings, according to some accounts, and other aircraft displayed signs of emergencies, such as losing radio communication with air traffic controllers or transmitting a distress signal.

Reports about these false alarms have revealed extraordinary circumstances around some of the incidents and bizarre explanations for how they arose. For example, it has been claimed that the pilots of one foreign aircraft approaching the U.S. set their plane's transponder to transmit a code signaling they had been hijacked simply to show authorities that they were aware of what had been taking place in America that morning. [1] Another aircraft reported as transmitting a distress signal while approaching the U.S. was subsequently found to have been canceled, and still at the airport. [2]

There may be innocent explanations for some of the less serious false alarms, such as those simply involving the temporary loss of radio communication with the plane, which is a common occurrence and happens on a daily basis. [3] But, viewed in its entirety, the evidence appears highly suspicious and raises serious questions. Why, for example, were there so many false alarms on September 11? Why did so many of them involve false reports of hijackings or aircraft falsely signaling that they had been hijacked? The details of specific incidents that have been reported, which I describe below, show that these false alarms must have been something more than just the results of confusion caused by the terrorist attacks.

MILITARY EXERCISES INCLUDED SIMULATED HIJACKINGSOne possibility to consider is that some of the false alarms related to training exercises taking place on September 11. There is evidence supporting this contention. For example, shortly after 9/11, the New Yorker reported, "During the last several years, the government regularly planned for and simulated terrorist attacks, including scenarios that involved multiple plane hijackings." [4] And we know that the North American Aerospace Defense Command (NORAD), the military organization responsible for defending U.S. airspace, was in the middle of a major exercise called Vigilant Guardian on September 11. [5] This exercise is known to have been scheduled to include at least one simulated plane hijacking on the morning of 9/11. [6] And in the week before 9/11, it included at least four simulated plane hijackings. [7]

The possibility that these false alarms were deliberate and intended to fulfill a sinister purpose needs to be seriously examined. Were they coordinated and pre-planned by rogue insiders working in the military and other U.S. government agencies, so as to ensure the attacks succeeded?

Were the false alarms that occurred at the same time as the attacks intended to cause confusion, and divert personnel and resources, thereby impairing the emergency response to the attacks? Colonel Robert Marr, the battle commander at NORAD's Northeast Air Defense Sector (NEADS) on 9/11, has indicated that this is what they achieved. He recalled: "There were a number of false reports out there. What was valid? What was a guess? We just didn't know." Major General Larry Arnold, the commander of the Continental United States NORAD Region (CONR) on 9/11, similarly recalled, "A number of aircraft [were] being called possibly hijacked ... there was a lot of confusion, as you can imagine." [8]

And were the false alarms that occurred after the attacks ended intended to prevent principled and honest military or government employees from promptly assessing what had happened, and determining how, against the odds, the attacks had succeeded? As Vanity Fair reported, tape recordings of the operations floor at NEADS reveal that "there was no sense that the attack was over with the crash of United 93," the last of the four hijacked aircraft. Instead, "the alarms go on and on. False reports of hijackings, and real responses, continue well into the afternoon. ... The fighter pilots over New York and DC (and later Boston and Chicago) would spend hours darting around their respective skylines intercepting hundreds of aircraft they deemed suspicious. ... No one at NEADS would go home until late on the night of the 11th." [9]

By tying up personnel, the false alarms could also have prevented anyone from making public information that contradicted the official 9/11 story that was being put out, and that would raise questions about who was actually responsible for the attacks. By the time a person with such information was free to reveal it, after the crisis calmed down, the official story would already have been extensively promoted to the public and generally accepted as true, and so it would be too late to effectively disclose information that would cast serious doubt on that account.

UP TO 29 PLANES REPORTED AS HIJACKEDSeveral accounts have indicated the large number of false alarms that occurred on September 11. For example, sometime between the attack on the Pentagon and the crash of Flight 93 in rural Pennsylvania, the Federal Aviation Administration (FAA) administrator, Jane Garvey, received a call from Leo Mullin, the CEO of Delta Air Lines. Mullin complained: "We can't find four of our planes. Four of our transponders are off." [10] (A transponder is a device that sends an aircraft's identifying information, speed, and altitude to air traffic controllers' radar screens.)

After the World Trade Center was hit the second time at 9:03 a.m., the FAA told all air traffic control facilities around the U.S. to notify it of anything unusual that occurred. In response, facilities reported numerous incidents. [11] According to author Pamela Freni, "Upward to two-dozen [aircraft] were listed at one time, but ultimately the number was whittled to 11 highly suspicious cases." The list included the third and fourth aircraft targeted in the attacks--American Airlines Flight 77 and United Airlines Flight 93--and nine false alarms. [12]

Regarding, specifically, incorrect reports of planes being hijacked, the 9/11 Commission Report stated, "During the course of the morning, there were multiple erroneous reports of hijacked aircraft." [13] Defense Department spokeswoman Victoria Clarke, who was in the Pentagon during the attacks and for most of the rest of September 11, has recalled: "There were lots of false signals out there. There were false hijack squawks, and a great part of the challenge was sorting through what was a legitimate threat and what wasn't." [14] Larry Arnold has said, "By the end of the day, we had 21 aircraft identified as possible hijackings." [15] Robert Marr recalled, "At one time I was told that across the nation there were some 29 different reports of hijackings." [16]

I describe below details of some of the flights that were among the false alarms on September 11. Firstly, I examine nine flights that were mistakenly considered to have been hijacked. I then examine flights for which we either do not know the nature of the false alarm, due to the lack of available information (so the aircraft may have been a suspected hijacking, but this fact has not been reported), or the emergency is known to have been something other than a suspected hijacking, such as a loss of radio contact with the aircraft.

AIRCRAFT FALSELY REPORTED AS HIJACKED ON 9/11

• Flight 11 Reported as Still Airborne After Hitting WTCThe first of the "multiple erroneous reports of hijacked aircraft," according to the 9/11 Commission, was a report that American Airlines Flight 11 was still airborne and heading toward Washington, DC, more than half an hour after this plane crashed into the World Trade Center. [17]

Colin Scoggins, the military liaison at the FAA's Boston Center, called NEADS at 9:21 a.m. and said: "I just had a report that American 11 is still in the air, and it's on its way towards--heading towards Washington. ... It was evidently another aircraft that hit the tower." However, Boston Center controllers were not tracking this alleged flight, heading toward Washington, on radar. Instead, according to Vanity Fair, "The plane's course, had it continued south past New York in the direction it was flying before it dipped below radar coverage, would have had it headed on a straight course toward DC." Scoggins has claimed he got the erroneous information about the flight from an FAA teleconference he was monitoring. He said he thought someone was overheard "trying to confirm from American [Airlines] whether American 11 was down," and that "somewhere in the flurry of information zipping back and forth during the conference call this transmogrified into the idea that a different plane had hit the tower, and that American 11 was still hijacked and still in the air." [18]

• United Airlines Plane Reported as Hijacked, but Still at AirportAnother early false report of a hijacking occurred at 9:25 a.m., when Marcus Arroyo, the security division manager for the FAA's eastern region, called Mark Randol, the manager of the FAA's Washington, DC, Civil Aviation Security Field Office, and alerted him to several hijackings. Arroyo mentioned Flight 175 and Flight 77 (the second and third aircraft actually targeted that morning), but also said, incorrectly, that another aircraft, United Airlines Flight 177, had been hijacked. Randol's staff soon discovered that Flight 177 was still on the ground at Logan International Airport in Boston, being held at the gate there. [19] No explanation has been given for why Flight 177 was falsely reported as a hijacking.

• Delta 1989 Gave Numerous Indications of Being HijackedDelta Air Lines Flight 1989 was a Boeing 767 bound from Boston to Los Angeles, which repeatedly acted suspiciously and was repeatedly suspected of being hijacked. The aircraft was first suspected of being hijacked at around 9:30 a.m. when controllers at the FAA's Cleveland Center who were monitoring it mistakenly thought the sounds of Flight 93 being hijacked, heard over radio, had come from Delta 1989. But they soon decided that Flight 93 was the source of the communications and that Delta 1989 was not hijacked. [20]

However, at around 9:40 a.m., Colin Scoggins at the FAA's Boston Center called NEADS and said the Boston Center believed Delta 1989 was a hijacked aircraft. [21] It is unclear why Scoggins made this claim, and also why he considered it his responsibility to call NEADS about Delta 1989, since the flight was at that time being tracked by the Cleveland Center, not the Boston Center. [22] The 9/11 Commission Report suggested that Boston Center managers had noted the similarities between Delta 1989 and the two aircraft that had hit the WTC: all were 767s flying from Boston to Los Angeles, which had taken off around the same time. The managers also remembered a radio transmission the center heard, apparently made by a hijacker on Flight 11, saying, "We have some planes," and consequently "guessed that Delta 1989 might also be hijacked." [23]

Over the next 30 to 35 minutes, Delta 1989 repeatedly behaved strangely, creating further suspicion that it might have been hijacked. Delta Air Lines instructed the flight to land in Cleveland, but did not inform air traffic control of this. Consequently, Cleveland Center controllers became suspicious when the plane's pilot contacted them, requesting an immediate change of course. Their level of concern increased when he failed to respond to a message as his plane descended toward Cleveland. [24] Then controllers at another facility had their suspicions of the flight increased when the pilot failed to use standard, and highly important, terminology in his radio communications with them. [25]

Delta 1989 landed at Cleveland Hopkins Airport at around 10:18 a.m. and was directed to a remote area. [26] FBI agents and a police SWAT team approached it, in case any problems arose. [27] It was about two hours after the plane landed that the passengers were allowed off, and it was around mid-afternoon before it was finally confirmed that the flight had never been hijacked. [28]

• Continental Airlines Plane Transmitted Hijack Signal Three TimesAnother incident appears to have occurred at around 9:35 a.m., as it was reported at 9:36 a.m., in a phone call between John White, a manager at the FAA's Command Center in Herndon, Virginia, and Doug Davis, the special assistant for technical operations in air traffic services at FAA headquarters. White told Davis that Continental Airlines Flight 321, which was "en route from Cleveland to Denver," had "squawked hijack three times." In other words, the pilot had set the plane's transponder to transmit the code of "7500," which signals that the flight has been hijacked. But, White added, "we have made contact with the pilot and the pilot has told us everything is okay." Just over an hour later, White informed Davis that Flight 321 was "on the ground at Peoria," Illinois, and the FBI was "approaching the aircraft at this time." Although White told Davis, "We are trying to determine why he squawked hijack," further details of this false alarm are unreported. [29]

• American Airlines 189 Sent Text Message Signaling a HijackingEmployees at the American Airlines System Operations Control (SOC) center in Fort Worth, Texas, became concerned when they temporarily lost communication with one of their planes, and the center also received a message from that plane incorrectly signaling it had been hijacked. Radio contact was lost with the Boston-to-Seattle flight at 9:45 a.m. According to the Wall Street Journal, "Everyone in the room [at the SOC] was convinced it was a ... hijacking." [30]

Evidence indicates this aircraft was American Airlines Flight 189. [31] Donald Robinson, a dispatcher at the SOC, received what he has called a "hijack message" from Flight 189, via the ACARS text messaging system. Robinson then sent a text message back to the plane's pilots, asking them if they were "squawking" the universal code for a hijacking. Ten minutes after communication with Flight 189 was lost, contact was restored. The problem, according to the Wall Street Journal, was due to a "radio glitch." Though Robinson suggested that the pilots may have sent the "hijack message" accidentally, he admitted that it was "unknown why the cockpit sent this message." [32]

• Possible Hijacked Aircraft Heading to U.S. from CanadaAround 10:00 a.m., a Canadian NORAD unit called NEADS and told it that a suspected hijacked aircraft was heading south from Canada, toward Washington, DC. [33] Few details were revealed about this plane. A member of staff at NEADS informed their colleagues that it was from an "unknown departure airport," and they did not "know any codes or anything" else about it. [34] When someone at NEADS then called the Canadian unit for more information, the person who answered the call only said they had seen "something on the chat"--meaning NORAD's computer chat system--about a "possible" aircraft. A few minutes later, the Canadian unit called NEADS again and said the suspected hijacking was a false alarm. The caller said the unit's intelligence team was "not assessing that there's an actual aircraft problem. It's just that there could be problems from our area." He added, "There's no actual aircraft that we suspect as being a danger." [35]

• Korean Airlines 85 Repeatedly Indicated it was HijackedOne of the aircraft mistakenly suspected of being hijacked on September 11 about which most has been reported is Korean Airlines Flight 85. This plane gave several indications that it had been hijacked, was tailed by fighter jets, and was even threatened with being shot down by the military.

KAL 85 was a Boeing 747 with 215 people on board, flying from Seoul, South Korea, to New York. It had been due to land in Anchorage, Alaska, for a refueling stop when problems began. Shortly before midday, it was discovered that the plane's pilots had sent a text message that included the letters "HJK," the code for a hijacking. [36] Then, after KAL 85 entered their airspace at around 1:00 p.m., Anchorage air traffic controllers asked the pilots coded questions over radio to see if the plane had indeed been hijacked. But instead of giving reassurance that the plane was safe, the pilots switched their transponder to "7500," the code signaling a hijacking. KAL 85 continued transmitting this code for the next 90 minutes, until it landed. [37] In fact, according to an official report, "There were five separate and ongoing indicators of a hijacking situation" on KAL 85, although the report did not specify what those indicators were. [38]

NORAD launched fighter jets to follow KAL 85, ordered that the plane be directed away from Anchorage, and threatened to have it shot down if it refused to change course. [39] KAL 85 was redirected to Whitehorse Airport in Canada. It was escorted there by fighters and landed without incident at 2:54 p.m. [40] Only on the following morning, after a bomb-sniffing dog searched the plane and its cargo was checked, did the Royal Canadian Mounted Police finally confirm that KAL 85 was never hijacked. [41]

KAL 85 has subsequently been treated with much secrecy. The FAA, NORAD, and Transport Canada have declined to answer questions about it. [42] Korean Airlines refused to make available a tape recording of conversations between the pilot and airline officials in Anchorage, and has not even revealed the names of the members of the plane's flight crew on September 11. [43]

In light of the possibility that some of the false alarms on September 11 related to training exercises taking place that day, it is notable that, a few days earlier, one of those exercises included a scenario where an aircraft remarkably similar to KAL 85 was hijacked. On September 6, NORAD's exercise Vigilant Guardian included a simulated scenario in which a plane, Korean Airlines Flight 357, was taken over by terrorists. KAL 357, like KAL 85, was a Boeing 747 flying from Seoul to Anchorage. And on September 6, similar to what it did in response to KAL 85 five days later, NORAD ordered its Alaskan region to intercept and shadow the hijacked plane, and directed fighter jets to get in a position to shoot the plane down if necessary. [44]

• San Diego to Denver Flight Suspected as HijackedAt some unspecified time, apparently early in the afternoon, it has been reported that NORAD's operations center in Cheyenne Mountain, Colorado, was receiving "reports of a hijacking out of San Diego, California," that was "headed to Denver." Eventually, the aircraft identified itself and landed uneventfully. Further details of this flight are unknown. [45]

• Possibly Hijacked U.S. Airways Flight Approaching From SpainThe last aircraft incorrectly suspected of being hijacked on September 11, according to CONR's Larry Arnold, was a U.S. Airways flight approaching the United States from Madrid, Spain. [46] At 3:20 p.m., it was reported over an FAA teleconference that the White House was saying this flight was heading to Philadelphia International Airport, and the military was scrambling fighter jets in response to it. Accounts conflict over whether the U.S. Airways plane was Flight 930 or Flight 937. [47] Lewis Libby, Vice President Dick Cheney's chief of staff, who was in the Presidential Emergency Operations Center below the White House, has recalled, "When we first got word [of the flight], we got word that it was only 30 minutes or so outside of U.S. airspace." Libby indicated that the plane's transponder had been transmitting the code for a hijacking, saying, "I think it was one of those ones where there was an actual report that it was showing hijacking through some electronic signal." [48]

After a short time, the flight was found to be secure. Arnold has recalled that Robert Marr called him from NEADS and said, "We just talked to the airline, and that aircraft is back on the ground in Madrid." [49] According to Libby, "It turned out that, I think, it was only 35 minutes out of Spanish airspace, not out of our airspace." [50]

OTHER AIRCRAFT EMERGENCIES, AND UNSPECIFIED AIRCRAFT EMERGENCIES, ON 9/11

• Coast Guard Reported Three Suspicious Aircraft, but One Flight 'Never Existed'As previously mentioned, there were some false alarms on September 11 for which the specific nature of the emergency is unstated. These may have been suspected hijackings or they may have been something else, like the loss of radio contact or the loss of a transponder signal. An example of this is an incident that occurred shortly after 11:00 a.m., when three suspicious flights were reported as approaching the U.S.

At 11:18 a.m., it was reported on an FAA teleconference that the Coast Guard in Norfolk, Virginia, had received distress signals from Air Canada Flight 65, Continental Airlines Flight 57, and United Airlines Flight 947. Whether these distress signals were the "7500" transponder code signaling a hijacking, or something else, is unreported. The three aircraft were reported as being over the Atlantic Ocean. Jeff Griffith, the deputy director of air traffic at FAA headquarters, subsequently instructed John White at the FAA's Command Center to alert NORAD to the aircraft, and to also notify the Air Traffic Services Cell (ATSC), an office at the Command Center manned by military reservists.

By 11:46 a.m., it was determined that the distress signals were false alarms. It was reported on the FAA teleconference that "all three aircraft ... are accounted for" and "all are OK." The United Airlines plane returned to Europe and the Continental Airlines flight landed in Gander, Canada. Remarkably, it was discovered that Air Canada 65 hadn't even been airborne. White reported that it "landed last night and was scheduled to depart today, but the flight's canceled." [51] According to an ATSC chronology of the events of 9/11, this flight "never existed." [52]

• FAA Command Center Compiled List of 11 Suspicious AircraftAs mentioned earlier, following the second attack in New York, the FAA's Command Center instructed air traffic control facilities to notify it of anything unusual. In response, according to Linda Schuessler, the deputy director of system operations at the Command Center, "we started getting more and more calls about bomb threats, about aircraft that we had lost communication or radar identification with." This led to the center compiling a list of 11 aircraft "that we had gotten unusual information on, that we thought seemed worthy of keeping a closer eye on." The list included two of the planes targeted in the terrorist attacks, Flight 77 and Flight 93. [53]

Various accounts have indicated details of the other flights singled out by the Command Center. A 9:10 a.m. entry in a chronology of events at the Command Center on September 11 mentioned seven aircraft for which the center was providing "coordination to assist in finding," although evidence indicates that at least some of these aircraft only aroused suspicion later on than 9:10 a.m. One of the aircraft was Delta Air Lines Flight 1989 (see above). The other six, and the few details we know about them, are as follows:

- American Airlines Flight 2247: At 10:04 a.m., the FAA's Fort Worth Center reported this flight to the Command Center. The aircraft, going from Orlando, Florida, to Shreveport, Louisiana, was "NORDO," meaning radio contact with it had been lost. Communication was restored by 10:17 a.m.

- U.S. Airways Flight 41: The FAA's Memphis Center reported this plane, going from Charlotte, North Carolina, to Los Angeles, to the Command Center. The reason for the report is unknown.

- Northwest Airlines Flight 197: The Command Center appears to have been alerted to this plane, en route from Lansing, Michigan, to Minneapolis, Minnesota, at 10:03 a.m. The reason for the report is unknown. Flight 197 subsequently landed in Marquette, Michigan.

- United Airlines Flight 641: United Airlines lost contact with this plane at around 10:00 a.m., but persistent attempts to communicate with it were eventually successful. The flight subsequently landed in Detroit, Michigan.

- United Airlines Flight 57: This aircraft was reported as missing sometime between 10:55 a.m. and 11:15 a.m. It appears to have been reported to the Command Center by controllers at Denver International Airport, for reasons that are unknown. It subsequently landed in Garden City, Kansas.

- U.S. Airways Flight 633: At 10:55 a.m., controllers at Philadelphia International Airport reported that they had "lost" this flight, which was heading to Las Vegas. The Command Center chronology indicated that the plane subsequently landed at the Philadelphia airport, at 11:14 a.m. [54]

Other accounts have mentioned three additional suspicious aircraft that were on the Command Center's list. (However, if these accounts are correct, it would indicate that the list included 12 aircraft, not 11.) One of the aircraft was a U.S. Airways flight heading to Chicago that was not communicating with air traffic controllers. [55] Another was a TWA flight that was refusing to land in Pittsburgh, and instead wanted to fly on to Washington. The third was a Midwest Express flight that disappeared from radar over West Virginia. [56]

Schuessler has recalled that Command Center personnel later "continued to say [they had] a little discomfort about the information [they] received" about these suspicious flights. But, she said, "We followed up with the security people and got enough information that the specialists here felt very comfortable that they understood the situation." [57]

• United Airlines Worker in England Received Suspicious Call from PilotAt around 11:16 a.m. (U.S. Eastern time), a United Airlines aircraft maintenance officer at a facility in London, England, received a brief but suspicious phone call from an unidentified aircraft, in which the caller--apparently the plane's pilot--sounded distraught, possibly as if he was being choked. The maintenance officer recognized the call as coming from a particular type of satellite phone that is available on Boeing 767s and 777s, although he believed it was most likely from a 777. He told the 9/11 Commission that the caller sounded strange, and that this was the "only phone call that he'd ever received of that nature in the 10 years he's been on the job for United."

The maintenance officer contacted a United Airlines maintenance facility at San Francisco International Airport to report the suspicious call, and it in turned notified the FBI. The FBI was told that the maintenance officer had said the caller from the plane "sounded as if they were being choked," although the maintenance officer later claimed he was unsure whether this had been the case. [58]

• Other Suspicious FlightsWe know of numerous other flights on September 11 that raised concern, although the reported details of these are scant. Andrew Studdert, United Airlines' chief operating officer at the time of the attacks, told the 9/11 Commission that at around 10:00 a.m., as well as losing contact with Flight 641 (see above), United lost contact with two more of its planes, Flights 399 and 415. Studdert also said that between 10:55 a.m. and 11:15 a.m., as well as Flight 57 (see above), eight other United planes were reported as missing. These were Flights 103, 634, 1211, 1695, 2101, 2102, 2256, and 2725. All of them were eventually located at various airports. [59] Furthermore, a Secret Service timeline stated that at 10:55 a.m., United Airlines Flight 182, from Boston to Seattle, was "unaccounted for." [60]

As previously mentioned, the temporary loss of radio contact with aircraft is a common occurrence. [61] And an order issued by the FAA at 9:45 a.m., for all aircraft over the U.S. to land at the nearest airport, presumably complicated interactions between pilots and air traffic controllers. [62] But can these factors account for a single airline losing communication with so many of its planes, all on the same day, and all within such short spaces of time? And on September 11, 2001, of all days, when two of the aircraft targeted in the terrorist attacks belonged to that particular airline?

Additionally, Studdert told the 9/11 Commission that throughout the morning of September 11, United Airlines received "a torrent of reported bomb threats; explosions are reported at two airports, and there are reports of other threats and other hijackings." These turned out to be "misunderstandings or hoaxes," but, Studdert commented, "the presumed threats cannot be dismissed in the high uncertainty of the moment." [63]

It seems reasonable to assume there were other false alarms that have not yet come to light. If Larry Arnold's claim of "21 aircraft identified as possible hijackings" or Robert Marr's claim of "29 different reports of hijackings" are anywhere near accurate, then there must have been additional false reports of hijackings beyond what I have described.

Who or what caused these false alarms? What effect did they have on the ability of the military and other U.S. government agencies to respond to the actual attacks, and to then assess how those attacks had been able to succeed? These questions have not yet been adequately addressed, and need to be investigated thoroughly.